White pulp of spleen: Filters lymph.

Correct Answer: B

Rationale: White pulp filters blood, not lymph; lymph filtration occurs in lymph nodes.

Correct Answer: C

Rationale: Primary nodules contain inactive B-lymphocytes; secondary nodules have active ones.

Correct Answer: C

Rationale: Spleen filters blood , forms blood in fetal life , destroys RBCs and has immune functions ; lymphocyte formation in germinal centers is more lymph node-specific (C is less accurate).

Correct Answer: C

Rationale: Microglial cells are macrophages in the central nervous system (CNS).

Correct Answer: A

Rationale: Acute tonsillitis causes regional lymph node inflammation ; metastasis is cancer-related , eosinophilia/basophilia are less typical (C, D).